Development of Clean Diesel Demonstration Vehicle with Alternative Combustion and Multivariable Control System, 03-R9636

Principal Investigators
Gary D. Neely
Jayant Sarlashkar
Shizuo Sasaki

Inclusive Dates:  07/01/06 – Current

Background - Increasing fuel prices around the world have spurred interest in more fuel-efficient vehicles such as diesel-powered and hybrid-electric vehicles, which also have higher initial costs than gasoline engines. The higher initial cost, or price premium, of these alternative power plants can often be recuperated in a few years as a result of reduced fuel costs, but the amount of the price premium is critical in the consumer's purchasing decision. However, emission regulations coming into effect during the next few years in Europe, Japan, and the United States will make it difficult for diesels to remain cost competitive. Meeting the future NO_x and particulate matter (PM) (problematic emissions for diesels) emissions standards will require exhaust treatment devices that may significantly increase prices. To keep the diesel engine as an attractive option, the emissions standards must be met while retaining a fuel economy advantage over gasoline engines and a price premium competitive or lower than a comparable hybrid powerplant. Minimizing the required exhaust treatment catalysts is one strategy for controlling the cost associated with meeting future emissions standards. If the amount of NO_x and PM formed during combustion can be reduced, the size of the required exhaust treatment devices can be reduced or possibly eliminated. Highly dilute combustion modes, like low-temperature combustion (LTC) and premixed controlled compression ignition (PCCI) have demonstrated the potential for large reductions in NO_x and PM. However, maintaining good combustion quality (stability and noise) for these low excess air combustion modes is a challenge for transient engine operation in a vehicle.

Approach - This project is concerned with developing new diesel engine control logic on a diesel-powered test vehicle that utilizes highly dilute combustion with low engine-out NO_x and PM emissions to minimize the required exhaust treatment for current and future emissions standards.

Accomplishments - This project was only recently initiated. Currently, the basic framework of the new engine control logic has been formulated as an airflow-dominant multi-variable structure, and the main control parameters for maintaining good combustion control are being investigated.

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